1. Technical Field
Embodiments of the inventive concept described herein relate to a semiconductor memory device, and more particularly, relate to a semiconductor memory device in which a plurality of memory dies are stacked on a substrate.
2. Discussion of Related Art
A mobile dynamic random access memory (DRAM) may be mounted in an electronic device such as a smartphone for a high-speed operation and low power consumption. Unlike flash memory, DRAM is volatile memory since it does not retain data stored therein when power is removed.
The DRAM may be implemented in the form of a multi-chip package to increase memory capacity. That is, the multi-chip package denotes a structure in which memory dies are vertically stacked in one package. For example, memory dies may be formed on an upper surface and a lower surface of a substrate in a multi-rank structure (e.g., a dual-rank structure), respectively. In the multi-rank structure, a memory die formed on the upper surface and a memory die formed on the lower surface may be capable of receiving a signal provided from a controller in common. Each of the memory dies may include a charge pump that generates a voltage using external power.